The present invention relates to a connection device that can be easily and quickly connected to an object, but is not easily disengaged from the object once secured thereto. More particularly, in one embodiment, the present invention relates to a connection device for quickly but securely connecting an electrical cable to an electrical terminal.
Normally, a conventional connection device such as a terminal is secured to a tapped base (i.e. a base having a threaded hole, and a bolt or a screw screwed into the threaded hole). There are many cases in which the secure connection of the terminal is very important. For example, if high voltage is supplied to the terminal or a substantial amount of current flows through the terminal, poor contact or disconnection of the terminal from the tapped base can lead to a disastrous accident. Poor contact or disconnection of the terminal can also result in the shut-down of working facilities, thereby adversely affecting operating efficiency. To prevent this, a variety of terminals have been proposed which will generally prevent unintentional disconnection of a terminal from its tapped base.
Examples of prior art terminals are shown in FIGS. 11a-11c. An O-shaped terminal 13 as shown in FIG. 11a and a U-shaped terminal 14 as shown in FIG. 11b are widely used today.
The U-shaped terminal of FIG. 11b can be easily engaged with and disengaged from the tapped base by merely loosening a fastened bolt, thus providing high workability.
However, in the event that the fixing bolt is slightly loose because it was not securely tightened or because it has loosened due to vibrations or the like, the U-shaped terminal 14 is apt to be undesirably disconnected from the tapped base. This is especially true when there is a tractive force acting on a cable attached to the terminal. Although unexpected disconnection of a U-shaped terminal from a tapped base can be prevented to some extent by providing the terminal with bent tip portions as shown for terminal 15 in FIG. 11c, this method has proven to be still ineffective to fully solve the problem of disconnection.
This unintentional disconnection of a terminal can be prevented by using a basic O-shaped terminal 13 as shown in FIG. 11a. This terminal will not become disconnected from a bolt or screw threaded into a tapped base, even if the bolt or screw is loose. Of course, however, a poor electrical connection can result from the bolt or screw being loose. A significant disadvantage to the O-shaped terminal 13 is that, whenever securing or removing the O-shaped terminal to and from a corresponding tapped base, the operator is obliged to manually remove the screw or bolt retaining the O-shaped terminal in position. In particular, if the screw or bolt is deeply threaded into the tapped hole of the base or if the thread pitch of the screw or bolt is very small, a significant amount of time is needed to fasten or remove the screw or bolt, thus resulting in an inefficient operation.
In addition to the use of the above-exemplified O-and U-shaped terminals as electrical terminals, such connection devices can also include parts for use in retaining a lid combined with a main body of a bag or a box so that the lid can be held in a closed position.